After do some tests, I finally find out this is an issue in Windows 10 UAP with VS 2015 CTP6.
The main reason of the issue is we used two different test namespace, Microsoft.VisualStudio.TestTools.UnitTesting & Microsoft.VisualStudio.TestPlatform.UnitTestFramework

Now we need to deeply view on it.

Microsoft.VisualStudio.TestTools.UnitTesting:
This is the namespace tool when you use testm/testc, the VS IDE will help you to add it to the namespace.

Microsoft.VisualStudio.TestPlatform.UnitTestFramework:
This is the default namespace when you created a new Win10 UAP test project.

By viewing the name of the namespace, test platform may a specified for testing UAP, that’s it.

The issue is caused by the Android 5.1 bug and there are two methods to solve the issue.METHOD 1:
Download the apk and change it to androidcheck.kiritostudio.comMETHOD 2:
Use the following command via adb(You can find the slim version of adb here):